Information encoding and transmission profiles of first-language (L1) and second-language (L2) speech.

Ann R Bradlow

doi:10.1017/s1366728921000717

Abstract

Inspired by information theoretic analyses of L1 speech and language, this study proposes that L1 and L2 speech exhibit distinct information encoding and transmission profiles in the temporal domain. Both the number and average duration of acoustic syllables (i.e., intensity peaks in the temporal envelope) were automatically measured from L1 and L2 recordings of standard texts in English, French, and Spanish. Across languages, L2 acoustic syllables were greater in number (more acoustic syllables/text) and longer in duration (fewer acoustic syllables/second). While substantial syllable reduction (fewer acoustic than orthographic syllables) was evident in both L1 and L2 speech, L2 speech generally exhibited less syllable reduction, resulting in low information density (more syllables with less information/syllable). Low L2 information density compounded low L2 speech rate yielding very low L2 information transmission rate (i.e., less information/second). Overall, this cross-language comparison establishes low information transmission rate as a language-general, distinguishing feature of L2 speech.

Highlights

When individuals know two or more languages, variation in the onset and extent of exposure to each language typically results in a functional imbalance across the first-language (L1), learned from early and extended exposure, and the second language (L2), learned from later and more limited exposure1
Inspired by information theoretic analyses of L1 speech and language production, this study proposes that L1 and L2 speech exhibit distinct information encoding and transmission profiles in the temporal domain
The present study compares speech timing patterns in L1 and L2 speech in three languages: English, French, and Spanish. This is done in terms of two key information theoretic parameters: information density and information transmission rate

Summary

Introduction

When individuals know two or more languages, variation in the onset and extent of exposure to each language typically results in a functional imbalance across the first-language (L1), learned from early and extended exposure, and the second language (L2), learned from later and more limited exposure. This study represents an initial step towards characterizing the language-general L1 versus L2 speech mode in quantifiable information theoretic terms that can be automatically applied to a multi-lingual multi-talker speech corpus. This empirical base can support further speculation and theorizing regarding cognitive mechanisms that underlie L1 versus L2 speech production and their impact on communicative efficiency (i.e., beyond speech intelligibility) under a variety of conversational conditions

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